After teenage Gloria Morgan marries middle-age Reggie Vanderbilt they have a daughter: the now famous fashion designer and heiress, Gloria Laura Vanderbilt.
It is the event and aftermath of her becoming heir to the Vanderbilt family fortune as a child that this mini-series focuses upon.
During her youth, both her maternal grandmother (Glynis Johns) and fundamentalist Catholic nanny (Maureen Stapleton) connive to turn 'Little Gloria' against her mother, after her father dies and leaves her 2.5 million dollars.
Since the Vanderbilt matriarch, Alice Gwynne Vanderbilt (Bette Davis) is living, the rest of the Vanderbilt estate is still hers. This leaves the younger Gloria's widowed and very young adult mother nearly penniless.
In an act of sibling rivalry, Reggie's less well favored sister (Angela Lansbury), buys off Gloria, Sr.'s gold digging mother (Johns); then, both women conspire to take 'Little Gloria' permanently away from her mother.
The true enough story becomes a media frenzy the winds up persecuting the wealthy child's mother and estranging them for life.